Conductive rubber electrode

ABSTRACT

A THROWAWAY ITEM FOR EFFECTING AN ELECTRICAL CONNECTION WITH THE SKIN COMPRISES A SKIN-CONTACTING ELECTRODE OF FLEXIBLE, CONDUCTIVE PLASTIC MATERIAL HELD AGAINST THE SKIN BY A PLIANT, ADHESIVE MEMBER TO WHICH THE ELECTRODE IS ADHERED. A TERMINAL IS MOUNTED ON THE ELECTRRODE AND EXTENDS THEREFROM TO PROVIDE A CONNECTION POINT FOR EXTERNAL ELECTRICAL APPARATUS, SUCH AS AN ELECTROCARDIOGRAPH MACHINE OR A HEART PACER. A CONNECTOR CLIP IS ELECTRICALLY CONNECTED WITH THE APPARATUS BY A LEAD AND IS ATTACHED TO THE TERMINAL AFTER THE ITEM IS APPLIED TO THE SKIN. THE METHOD OF APPLYING THE ITEM TO THE SKIN TO EFFECT AN ELECTRICAL CONNECTION THEREBETWEEN IS CHARACTERIZED BY PRESSURE RESPONSIVE ADHESIVE ATTACHMENT AND BY BOTH THE SKIN AND THE FACE OF THE ITEM IN CONTACT THEREWITH BEING DRY.

p 1971 R. o. woonsbu 3,606,881

' GONDUCTIVE RUBBER ELECTRODE Original Filed m 22, 1967 INVENTOR Riley 0. Woodson WEW BY RNEYS.

United States Patent Oflice Patented Sept. 21, 1971 Int. Cl. A61b /04 US. Cl. 1282.06E 2 Claims ABSTRACT OF THE DISCLOSURE A throwaway item for effecting an electrical connection with the skin comprises a skin-contacting electrode of flexible, conductive plastic material held against the skin by a pliant, adhesive member to which the electrode is adhered. A terminal is mounted on the electrode and extends therefrom to provide a connection point for external electrical apparatus, such as an electrocardiograph machine or a heart pacer. A connector clip is electrically connected with the apparatus by a lead and is attached to the terminal after the item is applied to the skin. The method of applying the item to the skin to effect an electrical connection therebetween is characterized by pressure responsive adhesive attachment and by both the skin and the face of the item in contact therewith being dry.

This application is continuation of application, Ser. No. 640,028 filed May 22, 1967 and now abandoned.

Medical apparatus such as an electrocariograph machine or a heart pacer require an external electrical connection with the skin of the patient. Heretofore, this has been eflected with a metallic electrode which is utilized in conjunction with a conductive paste spread on the skin. Not infrequently, the paste is a cause of skin irritation and is messy to handle. Besides this inconvenience, the electrode must usualy be strapped in place and is used with each patient, thereby requiring that the electrode be cleaned after each operation of the apparatus as a part of the general maintenance of the equipment.

It is, therefore, the primary object of this invention to provide an electrode device for making an electrical connection with the skin which is not subject to the inconveniences in handling and the irritation problem discussed above.

As a corollary to the foregoing object, it is an important aimof the instant invention to provide such a device in the form of a throwaway item which is used only once with a particular patient and then discarded.

A further and important object of the invention is to provide a device as aforesaid having a skin-contacting, conductive element which is flexible and thereby capable of conforming to the skin to effect the electrical connection without the use of conductive pastes or the like.

Still another important object is to provide such a device which is readily attached to the skin by a dry application method involving simple pressure application and without the use of straps, wrappings or the like.

In the drawing:

FIG. 1 is a plan view of the device prior to application to the skin of a patient, a portion of the adhesive member being broken away to reveal details of construction;

FIG. 2 is an elevational view of the device shown in FIG. 1;

FIG. 3 is a bottom view of the device;

FIG. 4 is a bottom perspective view of the device after removal of the inert facing;

FIG. 5 is an enlarged cross-sectional view of the device taken along line 5-5 of FIG. 1 illustrating the same in contact with the skin and showing a conductive clip connected to the terminal thereof;

FIG. 6 is a cross-sectional view of the terminal of the device looking upwardly in the illustration of FIG. 5 and showing a bottom view of the connector clip.

FIG. 7 is an exploded, perspective view of the device; and

FIG. 8 is an enlarged, fragmentary, cross-sectional detail of the foil and the electrode.

A thin, pliant, adhesive member 10 of circular shape has a skin-contacting undersurface 12 coated with a normally tacky and pressure-sensitive adhesive substance. Member 10 may take the form of a piece of adhesive tape cut to the desired size and shape, either of the fabricbacked or flexible plastic type as desired. Note in FIGS. 2 and 3 that surface 12, prior to application of member 10 to the skin, is covered with an inert facing in the form of a pair of tabs 14.

A thin, circular, plate-like electrode 16 has an upper face 18 in contact with a central zone of surface 12 and thus is adhered thereto due to the adhesive nature of such surface. Electrode 16, therefore, is in the form of a disc which is completely surrounded by an annular portion of surface 12 and presents a lower face 20 in contact with the skin 22 (FIG. 5) when the device is placed thereon. Electrode 16 is composed of an electrically conductive, synthetic resin material such as silicon rubber filled with an eletrically conductive, particulate substance, carbon, graphite, or silver being suitable for this purpose. The eletrode 16, therefore, is flexible and, together with member 10, is capable of conforming to the patients skin.

An upstanding terminal 24 is integral with a metallic foil 26 at its base, the foil 26 being of circular configuration, concentric with electrode 16, and sandwiched between the upper face 18 of electrode 16 and surface 12. Foil 26 has multiple apertures 28 therein to permit the tacky coating on surface 12 to adhere to face 18 at various places through the foil. A plurality of downwardly projecting protuberances 30 are formed in foil 26 by the application of a punch thereto when the foil is in place on electrode 16 but prior to the attachment of the electrode and foil to member 10. Thus, the upper face 18 of electrode 16 is pitted at each protuberance 30 as illustrated in FIG. 8, thereby assuring that a good electrical connection. is made at the interface of foil 26 and electrode 16.

FIG. 7 depects the assembly of the device and illustratrates that member 10 is provided with a hole 32 at its center and is slitted to permit member 10 to pass over an enlarged head 34 on terminal 24. Electrical contact is made with terminal 24- through the use of a spring wire connector clip 36 having a pair of legs 38 which are biased into embracing relationship to terminal 24 as illustrated. Clip 36 is covered with an insulated sheath or boot 40 having a clearance opening 42 therein for the head 34 of terminal 24. A lead 44 is electrically connected to clip 36 and extends therefrom to medical apparatus such as an electrocardiograph machine or a heart pacer.

In use acording to the method of the invention, tabs 14 are stripped from surface 12 and the electrode device is simply placed in overlying relationship to the skin 22 as illustrated in FIG. 5. Upon application of pressure to member 10 as the same is applied to the skin, the annular portion of surface 12 surrounding electrode 16 adheres to skin 22 much in the nature of a bandage and the lower face 20 of electrode 16 is held tightly in contact with the underlying skin. Being flexible throughout both as to member 10 and electrode 16, the device conforms to the skin to assure that face 20 is held in contact with the skin over substantialy its entire surface area to effect a good electrical connection between electrode 16 and the underlying skin.

Clip 36 is then attached to terminal 24 by squeezing boot 40 to spread the terminal contacting portions of legs 38 sufiiciently to permit the clip to be slipped over the head 34 of terminal '24, whereupon the legs 38 are released for spring movement of such portions into embracing engagement with the terminal. The head 34 serves to retain clip 36 on the terminal to prevent inadvertant disconnection thereof.

It may be appreciated from the foregoing that the electrode device of the instant invention is quite inexpensive and easy to manufacture, and thus may be employed as a throwaway item and discarded after use. The only part of the connecting circuitry between the medical apparatus and the patient that is permanent and reused is the lead 44 and the associated connector clip 36 which are trouble-free.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A device for connecting electrical apparatus to the skin comprising:

an adhesive member adapted to adhere to the skin upo contact therewith;

a flexible, dry, plate-like electrode element having a pair of opposed faces and composed of silicon rubber filled with a particulate, electrically conductive substance, said element being attached to said member and disposed for engagement with the skin when the member is adhered thereto; and

connection means for said apparatus electrically coupled with said element,

said member being thin and pliant and having a surface coated with a normally tacky and pressure-sensitive adhesive substance,

said surface having a zone thereof in contact with one of said faces to join the element to the member by adhesion,

said surface extending outwardly from said zone to present a portion thereof for contact with the skin, whereby to hold the other of said faces in engagement with the skin to establish an electrical connection therewith when the member is applied to the skin,

said connection means comprising a terminal provided with contact structure engaging said one face and mounting the terminal on the element,

said structure including a conductive foil overlaying said one face and sandwiched between the latter and said member,

said foil having an aperture therethrough permitting contact of said zone with said one face through the aperture.

2. A device for connecting electrical apparatus to the skin comprising:

an adhesive member adapted to adhere to the skin upon contact therewith;

a flexible, dry, plate-like electrode elements having a pair of opposed faces and composed of silicon rubber filled With a particulate, electrically conductive substance, said element being attached to said member and disposed for engagement with the skin when the member is adhered thereto; and

connection means for said apparatus electrically coupled with said element,

said member being thin and pliant and having a surface coated with a normally tacky and pressure-sensitive adhesive substance,

said surface having a zone thereof in contact with one of said faces to join the element to the member by adhesion,

said surface extending outwardly from said Zone to present a portion thereof for contact with the skin, whereby to hold the other of said faces in engagement with the skin to establish an electrical connection therewith when the member is applied to the skin,

said connection means comprising a terminal provided with contact structure engaging said one face and mounting the terminal on the element,

said structure including a conductive foil overlying said one face and sandwiched between the latter and said member,

said foil having a plurality of conductive protuberances projecting into said element through said one face.

References Cited UNITED STATES PATENTS WILLIAM E. KAM'M, Primary Examiner UJS. Cl. X.R.

12-8-4191, DIGEST 4 

